Rogue RDP Connections

Since I noticed my ethernet connection performance as being saturated on my Windows 2012 R2 server,  I ran the netstat command & noticed alot of ip addresses having established connections to 3389. When looking further, I see that these ip addresses are from many different countries like korea, china, russia, turkey... What can I do to prevent these rogue connections? Are they authenticating to my server? Could there be an app on the server thats allowing this?
See only one example below:
  C:\Windows\system32>netstat -na | find "3389"
  TCP    0.0.0.0:3389           0.0.0.0:0              LISTENING
  TCP    192.168.220.20:3389    81.25.47.69:57070      ESTABLISHED
  TCP    192.168.220.20:3389    81.25.47.69:57184      ESTABLISHED
yohayonAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Luis MenaCommented:
Check your server event security logs and see if someone got authenticated. Is this server hosted locally or cloud? like azure. Check your firewall
0
masnrockCommented:
What can I do to prevent these rogue connections?
Does the server need to have RDP enabled? It also sounds like you have it connected directly to your internet connection, versus being behind a firewall. The biggest question is do you need to have RDP open to the outside world? If not, then you need to make sure the rules of your firewall reflect that.

Otherwise...
Multifactor authentication would be another way to go about it.  If only certain IPs from the outside have reason to connect, you could make your firewall rules reflect such.
Other options include implementing an RDP gateway that uses TLS, or configuring things in a manner that forces someone to connect to a VPN in order to have access to the network to RDP into the server.

Regardless of what you choose, I recommend putting a hardware firewall into place.

Are they authenticating to my server?
Better check your logs. At a minimum they're getting prompted to authenticate. I'd assume the worst, because they're going to keep trying to brute force their way in (assuming that they haven't already). Hope your passwords are complex! And you may want to change them while in the process of securing things.

Could there be an app on the server thats allowing this?
You have RDP enabled in a way where parties can connect from the outside. That's a server configuration thing, not an application.
1

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Dirk-Jan SmitsLead EngineerCommented:
You could use
C:\> netstat -nao | find "3389"

to find the owning process id (ie: which process listens on port 3389)
 TCP    192.168.178.10:3389    192.168.178.69:53236   ESTABLISHED     1396

and then try
C:\> tasklist  | findstr 1396

to find the name of PID 1396. In my case this is 'svchost.exe' which is normal for 'real' RDP connections.
In your case it might be a different process.

Regards,
Dirk-Jan
0
Rajul RajInformation Security OfficerCommented:
Use wireshark for  analyzing the network. and if you want to find out how they are connecting ., try to do a Vulnerability assessment on your server. And first thing first, If you dont want your RDP service for the server , you can disable it.
0
Natty GregIn Theory (IT)Commented:
First is to note IP addresses and block them via firewall rules.
Disconnect the sessions or try and see what files and resources they are accessing as admin u should be able to remote in without disturbing the user.
Assume full breach and follow your companies guide line in breach protocol.

I would immediately remove affected machines from service until cleaned or rebuild.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Windows Server 2012

From novice to tech pro — start learning today.